B-flow imaging in low cervical internal carotid artery dissection.

OBJECTIVE: Generally, the vascular ultrasonographic examination is the first method in evaluation of internal carotid artery (ICA) dissection. B-flow imaging (BFI), conversely, is a newer method of vascular ultrasonography. The objective of this study was to assess the accuracy and efficacy of BFI for the diagnosis of low cervical ICA dissection. METHODS: Seventeen consecutive patients with 18 angiographically confirmed low cervical ICA dissections and 16 nondissected ICAs were studied with BFI and color Doppler ultrasonography (CDU). The results were compared with those of digital subtraction angiography. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of BFI in diagnosis of low ICA dissection were 94%, 94%, 94%, 94%, and 95%, respectively. Corresponding results for CDU were 83%, 94%, 94%, 83%, and 88%. B-flow imaging more precisely showed the intimal flap and the visualization of flow within the true and false lumens. In dissected carotid arteries, 6 intimal flaps were diagnosed with CDU, and 15 intimal flaps were diagnosed with BFI. The agreement between the observers in determining low cervical ICA dissection by BFI was found to be excellent (kappa = 0.80 for intramural hematoma; kappa = 0.93 for intimal flap). CONCLUSIONS: B-flow imaging seems to be a new reliable vascular ultrasonographic technique for evaluation of low cervical ICA dissection.